When there is any kind of research done on children, ethical guidelines require the researchers to obtain informed consent from the parent or guardian.
Articles tagged as
HB1639
NH Chiefs of Police Oppose Ethical Parental Rights Legislation that Affirms Federal Law Protecting Student Privacy
New Hampshire currently has a law that requires informed consent from parents when their children take a non-academic survey in school. Exploiting children while conducting research on them, is not only illegal, but it is unethical too.